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v3.19.1

Cumulative Preferred Stock (Characteristics of the First Preferred Shares) (Details) - $ / shares | 12 Months Ended
--- | ---
Dec. 31, 2018 | Dec. 31, 2013
Series A Preferred Stock [Member] |  |
Class of Stock [Line Items] |  |
Initial Yield | 4.40% |
Annual Dividend Per Share | $ 0.6388 |
Earliest Redemption and/or Conversion Option Date | Aug. 15, 2020 |
Preferred Stock, Redemption Price Per Share | $ 25 |
Right to Convert on a one for one basis | 1 |
Series A Preferred Stock [Member] | Minimum [Member] |  |
Class of Stock [Line Items] |  |
Initial Yield | 1.84% |
Series C Preferred Stock [Member] |  |
Class of Stock [Line Items] |  |
Initial Yield | 4.10% |
Annual Dividend Per Share | $ 1.1802 | $ 1.025
Earliest Redemption and/or Conversion Option Date | Aug. 15, 2023 |
Preferred Stock, Redemption Price Per Share | $ 25 |
Right to Convert on a one for one basis | 1 |
Series C Preferred Stock [Member] | Minimum [Member] |  |
Class of Stock [Line Items] |  |
Initial Yield | 2.65% |
Series F Preferred Stock [Member] |  |
Class of Stock [Line Items] |  |
Initial Yield | 4.25% |
Annual Dividend Per Share | $ 1.0625 |
Earliest Redemption and/or Conversion Option Date | Feb. 15, 2020 |
Preferred Stock, Redemption Price Per Share | $ 25 |
Right to Convert on a one for one basis | 1 |
Series F Preferred Stock [Member] | Minimum [Member] |  |
Class of Stock [Line Items] |  |
Initial Yield | 2.63% |
Series B Preferred Stock [Member] |  |
Class of Stock [Line Items] |  |
Initial Yield | 2.393% |
Earliest Redemption and/or Conversion Option Date | Aug. 15, 2020 |
Preferred Stock, Redemption Price Per Share | $ 25 |
Right to Convert on a one for one basis | 1 |
Series B Preferred Stock [Member] | Minimum [Member] |  |
Class of Stock [Line Items] |  |
Initial Yield | 1.84% |
Series H Preferred Stock [Member} |  |
Class of Stock [Line Items] |  |
Initial Yield | 4.90% |
Annual Dividend Per Share | $ 1.225 |
Earliest Redemption and/or Conversion Option Date | Aug. 15, 2023 |
Preferred Stock, Redemption Price Per Share | $ 25 |
Right to Convert on a one for one basis | 1 |
Series H Preferred Stock [Member} | Minimum [Member] |  |
Class of Stock [Line Items] |  |
Initial Yield | 4.90% |
Series I Preferred Stock [Member] | Minimum [Member] |  |
Class of Stock [Line Items] |  |
Initial Yield | 2.54% |
Perpetual fixed rate Series E Preferred Stock [Member] |  |
Class of Stock [Line Items] |  |
Initial Yield | 4.50% |
Annual Dividend Per Share | $ 1.125 |
Preferred Stock, Redemption Price Per Share | $ 26 |

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